At present, the PON, as a broadband optical access technology, usually uses a Point to Multi-Point (P2MP) topology. The PON includes an Optical Line Terminal (OLT), an Optical Distribution Network (ODN), and one or more Optical Network Units (ONUs). The OLT is located in a central office and connected to a service network through a service network interface, and implements access of multiple services according to a certain format. The ONU is located at a customer premise, and mainly implements service multiplexing/demultiplexing and user network interface functions. The ODN provides shared optical transmission media for a physical connection between the OLT and the ONU, uses a passive optical splitter to form a tree topology, and implement transparent transmission of a service. The ONU may also provide a Digital Subscriber Line (DSL) or an Ethernet (ETH) interface to connect a Residential Gateway (RG).
In IPv6, different DSLs usually use different IPv6 address prefixes. If a PON user adopts stateless address allocation, after receiving a Router Solicitation (RS) message sent by the user, a network entity Broadband Network Gateway (BNG) broadcasts a Router Advertisement (RA) message in all drop fibers in the PON, and then broadcasts the RA message through all DSLs to notify the user of an IPv6 address prefix allocated to the user. The RS message carries information about the IPv6 address prefix requested by the user, and the RA message carries the IPv6 address prefix allocated by the network entity to the user.
In the prior art, the network entity allocates an IPv6 address prefix to the user, and the IPv6 address prefix requested by each user is delivered through broadcast. That is, the user may receive all IPv6 address prefixes delivered by the network. Therefore, the user cannot determine the IPv6 address prefix delivered by the network for the user. Because different users require different IPv6 address prefixes to configure IP addresses, user IP addresses are configured in confusion.